April 25, 2024

Unusual Exotic Clasts in Chinese Lunar Samples Indicate Unexplored Terrane on Moon

Just Recently, Dr. Xiaojia Zeng, Prof. Xiongyao Li, and Prof. Jianzhong Liu from the Institute of Geochemistry of the Chinese Academy of Sciences (IGCAS) have recognized 7 unique igneous clasts in Chang e-5 samples from more than 3,000 Chang e-5 regolith particles.
This work was published in Nature Astronomy on December 22, 2022.
Particularly, the 7 unique clasts recognized are: a high-Ti vitrophyric fragment, a low-Ti basalt, an olivine-pyroxenite, a magnesian anorthosite, an evolved lithology, a Mg-rich olivine fragment, and a pyroclastic glass bead. The scientists associated these exotic igneous clasts with impact-ejected materials from other regions of the Moon, over 30-250 miles (50-400 km) away from the Chang e-5 mare unit.
By contrast with lunar rocks from the U.S. Apollo mission, the researchers found that 3 exotic igneous clasts in the Chang e-5 regolith displayed unusual petrological and compositional features.
The high-Ti vitrophyric piece showed distinct mineralogy among lunar basalts, most likely representing a brand-new type of lunar basalt.
The magnesian anorthosite clast, which was not observed in Apollo samples, offers proof that magnesian anorthosite is likewise a crucial element of the near-side lunar crust.
The pyroclastic glass records a compositionally distinct volcanic eruption on the Moon.
This study was the very first to acquire unique igneous lithologies from the 2 Gyr-aged basalt system of the Moon. This information will offer ground truth for modeling the provenance of regolith at the young mare unit of the Moon. The recognition of unusual lunar rocks in the Chang e-5 sample supplies proof that the lithological parts and magmatic activities of the lunar crust are more diverse than formerly believed.
This research recommends there are still unidentified geological units on the moon, which may help in planning future lunar expedition objectives.
Reference: “Exotic clasts in Chang e-5 regolith indicative of undiscovered terrane on the Moon” by Xiaojia Zeng, Xiongyao Li and Jianzhong Liu, 22 December 2022, Nature Astronomy.DOI: 10.1038/ s41550-022-01840-7.

Chang e-5 is a Chinese lunar expedition objective with the goal of collecting and returning samples from the Moon. It was released on November 24, 2020 and effectively landed on the lunar surface area on December 1. It is called after the Chinese moon goddess Chang e.
The recognition of uncommon lunar rocks in the Chang e-5 sample supplies proof that the lithological elements and magmatic activities of the lunar crust are more diverse than previously believed.

Graphical depiction of unique igneous clasts in Chang e-5 lunar regolith. Credit: IGCAS
Chang e-5 is a Chinese lunar expedition mission with the objective of gathering and returning samples from the Moon. It was launched on November 24, 2020 and successfully landed on the lunar surface on December 1.
The Chang e-5 objective touched down in the Mons Rümker region of the northern Oceanus Procellarum of the Moon and returned 3,816 pounds (1,731 kg) of lunar regolith.
Acknowledging exotic clasts (i.e., non-Chang e-5 locally derived materials) in the Chang e-5 regolith could offer important info about the lithological variety and regolith gardening procedure in the young mare region of the Moon.